Its name sounds like something out of science fiction, but the StarCAVE at the University of California, San Diego is now a science fact. The virtual-reality environment allows groups of scientists to venture into worlds as small as nanoparticles and as big as the cosmos – permitting new insights that could fuel discoveries in many fields. Early users of the StarCAVE include UC San Diego researchers in biomedicine, neuroscience, structural engineering, archaeology, earth science, genomics, art history and other disciplines.
Photo of Calit2 researchers explore proteins in 3D
Calit2 researchers explore proteins in 3-D from the Protein Data Bank, displayed inside the StarCAVE.
The StarCAVE is a five-sided virtual reality (VR) room where scientific models and animations are projected in stereo on 360-degree screens surrounding the viewer, and onto the floor as well. It was constructed by the UC San Diego division of the California Institute for Telecommunications and Information Technology (Calit2). At less than $1 million, the StarCAVE immersive environment cost approximately the same as earlier VR systems, while offering much higher resolution and contrast.
“When you’re inside the StarCAVE the quality of the image is stunning,” said Thomas A. DeFanti, director of visualization at Calit2 and one of the pioneers of VR systems. “The StarCAVE supports 20/40 vision and the images are very high contrast, thanks to the room’s unique shape and special screens that allow viewers to use 3-D polarizing glasses. You can fly over a strand of DNA and look in front, behind and below you, or navigate through the superstructure of a building to detect where damage from an earthquake may have occurred.”
A research paper about the design and construction of the StarCAVE appears in the current issue of the Elsevier journal, Future Generation Computer Systems (FGCS), and is available online at ScienceDirect.* DeFanti’s co-authors on “The StarCAVE, a Third-Generation CAVE and Virtual Reality OptIPortal,” include Calit2’s Gregory Dawe, Jurgen P. Schulze, Peter Otto, Javier Girado, Falko Kuester, Larry Smarr and Ramesh Rao (all at UC San Diego), as well as Daniel J. Sandin of the University of Illinois at Chicago’s Electronic Visualization Lab (EVL), and Javier Girado (now at Qualcomm Inc.).
The StarCAVE represents the third generation of surround-VR rooms. DeFanti’s team built and named the original Cave Automated Virtual Environment (CAVE) at the University of Illinois at Chicago in 1991. A second-generation model built ten years later at EVL is now the standard surround-VR technology and is widely used around the world and marketed by Mechdyne Corp. The first- and second-generation CAVEs require viewers to wear battery-powered ‘shutter’ glasses; the StarCAVE provides an improved 3-D experience and allows viewers to wear only lightweight, polarized ‘sun’ glasses.
Photo of Calit2 Director of Visualization Tom DeFanti inside the StarCAVE virtual reality system
Calit2 Director of Visualization Tom DeFanti inside the StarCAVE virtual reality system.
The room operates at a combined resolution of over 68 million pixels – 34 million per eye – distributed over 15 rear-projected walls and two floor screens. Each side of the pentagon-shaped room has three stacked screens, with the bottom and top screens titled inward by 15 degrees to increase the feeling of immersion (while also reducing the ghosting, or ‘seeing double’, that bedevils VR systems).
Because the StarCAVE is designed to help scientists, DeFanti and his team made sure to incorporate the latest in computer graphics processing – using 34 of the newest nVIDIA chips that can generate highly complex images. Thirty-four high-definition projectors (two per screen) create very bright left and right eye visuals, i.e. stereo or 3-D, per screen. Each pair of projectors is powered by a high-end, quad-core PC running on Linux, with dual graphics processing units and dual network cards to achieve gigabit Ethernet or 10GigE networking.
“With its advanced networking, the StarCAVE is the best virtual-reality portal within the OptIPuter network,” said Calit2’s DeFanti, co-principal investigator on the National Science Foundation-funded OptIPuter project. “That network now connects more than 20 so-called OptIPortals which are up and running around the world. They are ultra-high-resolution, tiled display walls, but for some researchers, flat display walls just aren’t enough: they want the realism that comes from the fully immersive 3-D experience that only a 360-degree VR room such as the StarCAVE can offer.”
Adding to the virtual reality in the StarCAVE is the surround sound system, which harnesses recent advances in wave field synthesis – a way to maximize the perception of many channels of sound emanating from different sides of the room. Calit2 also worked closely with Meyer Sound, Inc., to customize the installation of three arrays of five conventional high-quality speakers to provide 5.1 surround sound or up to 15 channels of discreet audio diffusion (with a subwoofer channel built into the floor structure).
Users of the StarCAVE can interact with the visuals on the 360-degree display – by pointing a “wand” that makes it easy to fly through the 3-D images and zoom in or out. The exact position of the wand and the user is determined by a multi-camera wireless tracking system.
Among the VR room’s other features, it is wheelchair accessible, and it was designed to withstand earthquakes. One of the StarCAVE’s five walls (along with its six projectors, three screens and three computers) rolls back on steel rails to provide access for users into the space, and the wall rolls back into place to provide the full 360-degree, immersive VR experience.
While the StarCAVE was in development, computer scientists were working on new applications to adapt computer programs for display in the VR environment. The room connects to the Protein Data Bank, so users can pull up one or multiple proteins and fly around them to find similarities and differences between the proteins. A virtual replica of Calit2’s headquarters building at UC San Diego, Atkinson Hall, has been used by neuroscientists who want to know if the human brain operates differently in virtual reality versus reality in ‘wayfinding’ situations.
“We also created an application which displays computer-aided design models of parts of the new San Francisco Oakland Bay Bridge,” said DeFanti. “The application allows users to walk/fly through these parts at their real size, to find material clashes, construction errors, and generally to draw conclusions about whether the structure could be built as designed.”
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3-D virtual reality environment by UCLA
New method devised for protecting private data
Companies and organizations that keep sensitive personal information on millions of Americans have become attractive targets for hackers in recent years, resulting in billions of dollars in losses for U.S. businesses and misery for countless consumers.
But now Amit Sahai, an associate professor of computer science at the UCLA Henry Samueli School of Engineering and Applied Science, and his colleagues have devised a new data-protection method they hope will put Internet criminals out of business.
"We want to change the rules of the game on hackers and even out the playing field," Sahai said.
Along with co-authors Brent Waters, a UCLA computer science alumnus, and Jonathan Katz of the University of Maryland, Sahai has come up with a mathematical system -- known as functional encryption -- that will not only help to simplify the encryption of data in servers but will also allow access to the data in an intuitive way, making it much harder for hackers to gain access to sensitive information but much easier for programmers to secure it.
While the method is not yet available for public use, it has received close attention from the data-encryption community. The authors' study, chosen as one of the top four papers at Eurocrypt 2008 -- one of two flagship international conferences in cryptography -- was presented this week at the conference in Istanbul.
In it, Sahai and his colleagues suggest that the biggest problem in data security today is that the world relies on "trusted servers" to store and secure data.
"This 'trusted server' model is a simple model," Sahai said. "It's easy to implement. It's easy to put into practice. Information is placed in the server at face value and the server itself is simply given the task of deciding who to give the data to. Because of the simplicity in programming, these servers have become ubiquitous and are prime targets -- everyone wants to attack them."
An additional problem with trusted servers, the authors say, is the current trend toward replicating data on a wide scale.
"To create robustness and availability, data is stored on several trusted servers as backups," said Waters, currently with the nonprofit research institute SRI. "If one server goes down, another can be accessed. There is a trade-off between data availability and security. The more replicated servers there are, the more targets there are for hackers."
The results of this lack of security speak for themselves. According to a 2007 FBI analysis, Internet crime costs U.S. businesses some $67 billion annually, including the indirect expense of repairing hacked systems. TJX, the parent company of discount clothing chains T.J. Maxx and Marshalls, revealed that during a recent 18-month period, hackers had stolen 45.6 million credit card numbers and other sensitive customer information. For every two Americans, one private record has been stolen through computer data breaches alone.
Cryptography, the practice and study of hiding information, is considered to be a branch of both mathematics and computer science and is closely tied to information theory, computer security and engineering. And while the technology of encryption has been around a long time, encrypting data and then deciding how to allow access to hundreds or even thousands of people has been a dilemma, Sahai said.
"Imagine current encryption technology as a lock and key -- the data is locked, and to allow different people access, many copies of the key need to be made," he said. "One record might need to be accessed by 10,000 people, so you make 10,000 copies of that key. With millions of documents and thousands of keys per document, you can imagine how very, very complicated it gets. It becomes much too complicated to manage. So even though we've had very strong encryption technology now for decades, it's just not used, or it is used incorrectly."
The study authors' new functional encryption method allows a programmer to simply plug in his criteria for the information. The mathematical system will then produce an encrypted record that only people matching the criteria can decrypt. The complex system of managing many keys is now simplified, and servers hold encrypted data that the servers themselves can't read. The information looks like gibberish to hackers.
In addition, the new mathematical system allows for keys to be personalized -- only one key is needed to unlock all the information that is available to that person.
"This is the key innovation in our system," Sahai said. "We have this mathematical method for randomization of personalizing keys so that your key doesn't just depend on what attributes you have, like what your name is. Further, there is some mathematical hardening that is personalized to you, so that you can't combine it with anyone else's keys to do anything meaningful."
The system severely restricts what a hacker can do. If he is an insider, he is limited by what access he legitimately has, and since keys are personalized, it becomes much easier to trace who accessed and released the information in the first place.
Sahai and Waters are considered the founders of the area of functional encryption. Sahai recently won a prestigious 2007 Okawa Research Grant Award from Japan's Okawa Foundation for his work in this area.
"Some of this work is already being implemented and is actually being incorporated into some research systems," Sahai said. "It's making its way closer to practice. Brent and I were able to apply for a patent on the very initial work we did, which was bought by a company called Voltage Security. There certainly is interest from the U.S. military and the U.S. Department of Homeland Security as well."
"Our goal is to rethink what encryption is," Waters said. "Over the years, people have taken on a somewhat rigid view of what encryption is. What we're hoping to do is show that we can build simpler and more powerful systems by changing the way we think. Eventually, we hope to get rid of complex infrastructures and do things in a simpler manner that is also more secure and cost-effective."
VIA
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Engineering Prof Builds Brains for Robotic Cars
Jonathan Sprinkle wants to build robotic vehicles that pass the Turing Test.
The test, proposed by Alan Turing in a 1950 paper, “Computing Machinery and Intelligence,” requires a robot’s behavior to be so lifelike that an observer can't tell if he’s dealing with a robot or a person.
Sprinkle, an assistant professor at The University of Arizona, and professor J. Mikael Eklund, of the University of Ontario Institute of Technology, have already passed the Turing Test with a control system they designed for a T-33 jet trainer. A veteran F-15 pilot who flew against the T-33 in a test at Edwards Air Force Base said it looked like a recent flight school graduate was at the controls.
Following his success with flight-based systems, Sprinkle has placed his robotic control expertise firmly on the ground, where he’s applying it to smart cars that drive themselves.
This research effort began with a DARPA Urban Challenge project Sprinkle worked on at the University of California, Berkeley. The Urban Challenge race took place in November, with smart vehicles driving themselves through 60 miles of simulated city traffic.
While the Urban Challenge got engineers involved in designing autonomous vehicles it didn’t foster robust designs, Sprinkle noted. As engineers faced tight deadlines, they hacked systems just to make them work instead of creating optimized, integrated designs. “The downside of that is that you don't get a holistic approach to the system,” said Sprinkle, who is with the UA’s electrical and computer engineering department.
Searching for Repeatable Results
“Some of the better teams out there had 30 to 40 people working on a single car,” he added. “And if they wanted to do this project again, they would have to have the same car. They would probably have to have exactly the same people. If they gave another team the code and the car, they probably couldn't make it run because there is so much knowledge involved in the order in which things start up.”
Obviously, these are not robust control systems that can be mass produced and bolted into thousands of vehicles.
Sprinkle would like to see the engineering community take a collective deep breath following the Urban Challenge, step back and design a system that isn't specific to one group of researchers or a single prototype vehicle.
The best way to do this is to work on each component of the system in detail, he said.
“In my research at UA, I want to give a small component of the system to each student, such as a path planner, and have them design a really solid one,” Sprinkle said. “I want to isolate the student to work on just one piece of the software to make it as robust as possible. I think that's where it needs to go. Each person understands a small piece of the problem in depth, and when you plug all those pieces together in the end, it should work.”
Simulations Save Time, Money
A lot of this new research is being done with computer simulations in Sprinkle's lab. Although field testing is an important part of vehicle development, Sprinkle believes much faster progress can be made initially with simulations because they don't require an expensive car and thousands of hours of tinkering with hardware.
Much of Sprinkle’s research is based on Model Predictive Control techniques, which involve combining models of various behaviors (such as obstacle avoidance) with data from the real world to calculate future moves (braking, turning or acceleration, for instance).
“You want to spend less time designing control algorithms, and more time telling the machine that certain things are good and certain things are bad and then having the control algorithm sort that out,” he said.
“If you see a traffic cone ahead when you're driving, for instance, you know that you can turn the steering wheel and don't need to change the accelerator,” he said. “You can just swerve out of the way. Sometimes you have to brake and use the accelerator in rapid succession, but, in your mind, you have a timeline for doing those various actions. Model Predictive Control follows the same logic. It's pretty magical, amazing stuff.”
The result is a control system that anticipates what will happen ahead and plans for future scenarios, rather than driving reactively in the present moment.
One way to further enhance Model Predictive Control would be to record the actions of a human driver and overlay the human’s driving style on the robotic system. “That would make it feel like a human is driving,” Sprinkle said. And the robotic car would move a step closer to passing the Turing Test.
Testing Multi-Core Sensors
In related research, Sprinkle is studying multicore computer processors. They offer a huge increase in computational speed and power, both of which are valuable for robotic cars. But there's a danger that they may make the system less stable.
Procedures that were previously handled by a single processor in linear fashion are now split up into shared tasks being done simultaneously by two or more processors. The processors are trading information, but there’s no guarantee that they're doing so at exactly the right time.
“We're doing some experiments to look at the possibilities of failure in these systems and to identify indicators that show when the system is failing,” Sprinkle said.
Cutting Sensor Costs
While autonomous vehicles now use lasers to learn about their environment, Sprinkle says large numbers of lasers aren’t practical for production cars. “If you want to build an autonomous car now, you basically have to start by buying $40,000 in lasers,” he said. “But if you can put something like a video camera in the car to help gather data, reducing the number of lasers, you'll have a more affordable, lower-cost sensor system.”
Although autonomous cars are experimental these days, Sprinkle believes that in 10 or 20 years we may see cars that can pull out of the parking garage and drive over to pick us up at the office.
But before that happens, there's plenty of research to be done by thousands of people.
“These procedures are couched in a really serious amount of nonlinear systems equations, and nonlinear differential equations,” Sprinkle said. “The problem is how you change that math into something that executes on a computer. That's where software engineering needs to go.
“That's what I really want to teach my students. Otherwise, we're just teaching them to compile things – and that's no fun – and how to do data structures. Data structures have already been done. It's not new.
“I don't want just any data structure,” he said. “I want a data structure that will drive my car.”
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MIT develops energy-efficient microchip
Researchers at MIT and Texas Instruments have unveiled a new chip design for portable electronics that can be up to 10 times more energy-efficient than present technology. The design could lead to cell phones, implantable medical devices and sensors that last far longer when running from a battery.
The innovative design will be presented Feb. 5 at the International Solid-State Circuits Conference in San Francisco by Joyce Kwong, a graduate student in MIT's Department of Electrical Engineering and Computer Science (EECS).
Kwong carried out the project with MIT colleagues Anantha Chandrakasan, the Joseph F. and Nancy P. Keithley Professor of Electrical Engineering, and EECS graduate students Yogesh Ramadass and Naveen Verma. Their Texas Instruments (TI) collaborators are Markus Koesler, Korbinian Huber and Hans Moormann. The team demonstrated the ultra-low-power design techniques on TI's MSP430, a widely used microcontroller. The work was conducted at the MIT Microsystems Technology Laboratories, which Chandrakasan directs.
The key to the improvement in energy efficiency was to find ways of making the circuits on the chip work at a voltage level much lower than usual, Chandrakasan explains. While most current chips operate at around one volt, the new design works at just 0.3 volts.
Reducing the operating voltage, however, is not as simple as it might sound, because existing microchips have been optimized for many years to operate at the higher standard-voltage level. “Memory and logic circuits have to be redesigned to operate at very low power supply voltages,” Chandrakasan says.
One key to the new design, he says, was to build a high-efficiency DC-to-DC converter-which reduces the voltage to the lower level-right on the same chip, reducing the number of separate components. The redesigned memory and logic, along with the DC-to-DC converter, are all integrated to realize a complete system-on-a-chip solution.
One of the biggest problems the team had to overcome was the variability that occurs in typical chip manufacturing. At lower voltage levels, variations and imperfections in the silicon chip become more problematic. “Designing the chip to minimize its vulnerability to such variations is a big part of our strategy,” Chandrakasan says.
So far the new chip is a proof of concept. Commercial applications could become available “in five years, maybe even sooner, in a number of exciting areas,” Chandrakasan says. For example, portable and implantable medical devices, portable communications devices and networking devices could be based on such chips, and thus have greatly increased operating times. There may also be a variety of military applications in the production of tiny, self-contained sensor networks that could be dispersed in a battlefield.
In some applications, such as implantable medical devices, the goal is to make the power requirements so low that they could be powered by “ambient energy,” Chandrakasan says-using the body's own heat or movement to provide all the needed power. In addition, the technology could be suitable for body area networks or wirelessly enabled body sensor networks.
“Together, TI and MIT have pioneered many advances that lower power in electronic devices, and we are proud to be part of this revolutionary, world-class university research,” said Dr. Dennis Buss, chief scientist at Texas Instruments. “These design techniques show great potential for TI future low-power integrated circuit products and applications including wireless terminals, battery-operated instrumentation, sensor networks and medical electronics.”
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Utra-fast fibre lasers, dopey photons… what’s next?
To date, many commercial ultra-fast lasers – the kind that emit light in short pulses for laser machining or spectroscopy – have been based on solid-state technology using bulk optical components. However, they have several drawbacks, not least their large size and high production and maintenance costs – problems that can be solved by using optical fibre, rather than air, to carry the light.
“Fibre lasers could replace solid-state lasers for most uses, as well as open the door to new applications,” explains Mircea Guina, a researcher at the Tampere University of Technology in Finland.
Guina, the manager of the EU-funded Uranus project, foresees ultra-fast fibre lasers playing a key role in machining even smaller nanotechnology systems and in demonstrating practical new applications, such as optical coherence tomography, which is a 3D digital imaging technique used in medicine, among many other applications. “There are literally hundreds of uses,” he says.
The Uranus project proved fundamental in advancing the technology in Europe, allowing partner companies, such as laser manufacturers Fianium and Corelase, to take a leading role in the sector, and strengthening the position of Stratophase and NKT as suppliers of nonlinear crystals and photonic crystal fibres, respectively.
A giant leap in four years
“The technology and the sector today are incomparable to what they were like four years ago,” Guina notes.
Broadly, the Uranus researchers’ two main goals were to develop ultra-fast laser systems operating at different wavelengths, and to develop and test broadband fibre sources. They achieved both goals, and even surpassed their own expectations.
“Our research broke new ground – the number of research papers we published is proof of that,” Guina says. For the more technical readers, Uranus’ major achievements include the first-ever demonstration of a so-called ‘mode-locked’ laser which uses a special fibre, ytterbium-doped photonic bandgap (Yb-PBG), as both a medium and method of compensating beam dispersion. This discovery contributed to the development of the first ‘supercontinuum fibre laser’ being sold as a ready-to-go system by Fianium.
“The supercontinuum source can generate pulses at all wavelengths,” explains Oleg Okhotnikov, the coordinator of the Uranus project. “For example, in the case of medical imaging you can select the wavelength you need from the broadband spectrum to detect a specific type of chromophore attached to a cancer cell.”
Such new applications are not the only benefit of ultra-fast fibre lasers. Compared to solid-state lasers, fibre systems are more efficient, smaller and cheaper to produce.
“Fibre is more efficient than air at getting the light to its target so it needs less power to achieve the same results as solid-state systems. It is also more stable and robust,” Okhotnikov says.
Three times cheaper
Fibre systems are also considerably cheaper. Though many of the uses for them are new, fibre laser systems have been around for some time. Much of the technology involved was first developed during the 1990s when optical fibre started to be used for communications. Not only does that mean that fibre systems are well tried and tested, it also means that the components – such as the diode pumps that power the laser pulses – are relatively cheap.
“Production costs for a fibre laser are considerably less than for a solid-state system. A fibre 20-watt system operating at less than 15 picoseconds [one picosecond is one trillionth of a second] costs around €50,000 compared to the €150,000 price of a solid-state system,” Okhotnikov says.
It is therefore not surprising that increasing numbers of industries requiring lasers are switching to fibre – a boon for the project partners. In the last four years, UK-based Fianium has doubled turnover each year and quadrupled its number of full-time staff, while opening sales offices in Asia and the United States. Meanwhile, Corelase, another Uranus partner and developer of the X-lase high-powered fibre laser, was acquired by European application developer Rofin-Sinar in early 2007, due in part to the success of its work in the project.
Since the end of Uranus, the team have presented proposals for new projects in order to continue their research.
“We have come a long way in recent years, but there are still many more areas to explore,” Guina says.
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